This invention relates generally to the assembly of pressure regulator parts, and more specifically in regulator apparatus in which seals are made or formed in response to such assembly.
When fluid pressure regulator parts are assembled, and a cap is screwed onto a body, a pressure seal or seals are directly made up or formed between regulator parts being assembled. Such seals are desirably made up by axial force only, i.e. free of relative rotation of interengaged surfaces at the seals, since such relative rotation can and does cause surface distortions which can lead to seal failure, fluid leakage, and/or undesirable particle generation. There is need for simple, effective, reliable means to prevent such sealing surface distortions in devices of this type.
In one example, the problem arises during the assembly of a pressure regulator in which a first seal is made between a pressure controlling diaphragm and a valve body. The first seal is made by having threads in the body which engage mating threads in cap engagement. When the cap is turned clockwise, it exerts an axial force on a thrust sleeve which transmits this force to a diaphragm and forces the diaphragm against the body at the seal. The problem arises because the cap also exerts a rotational force on the thrust sleeve which transmits this rotational force to the diaphragm. This rotational force may cause the diaphragm to rotate relative to the body. The combination of axial force and rotation of the diaphragm against the body can damage the effectiveness of the seal and may also create unwanted particles. In high-purity regulators, minimization of particles is exceedingly important.
In another example the problem arises when a poppet is screwed into a poppet holder, which is done after the seal has been made as described above. Tightening the poppet puts torque on the poppet holder as well as on a spring support. Since these parts clamp the diaphragm firmly to form a second seal, this torque is transmitted to the diaphragm, which can cause the second seal to rotate relative to the first seal. This relative rotation of the inner and outer portions of the diaphragm can cause wrinkling and other unwanted distortions of the diaphragm.
It is extremely important that the unwanted rotations described above be eliminated, and it is the purpose of this invention to accomplish this.